Offshore drilling platform



July 20, 1965 E. P. SWATEK, JR 3,195,313

OFFSHORE DRILLING PLATFORM Original Filed Feb; 9, 1959 I 5 SheetsSheet 14/ i in 0 M I i H :2 :i 1 U INVENTOR. EDWIN P. SWATEKJR.

20, 119-65 E. P. SWATEK, JR 3,195,313

" OFFSHORE DRILLING PLATFORI Qrmnal Filed ma. 9, 1959 s Sheets-Sheet 2i9. 7. mvsmoa.

EDWIN P. SWATEK,JR

ATTORNEY July 20, 1965 E. P. SWATEK, JR 3,195,313

OFFSHORE DRILLING PLATFORM Original Filed Feb. 9, 1959 5 Sheets-Sheet 3i INVENTOR.

i EDWIN P. SWATEK,JR.

4.4.1.5, 2M fM ATTORNEYS.

July 20, 1965 E. P. SWATEK, JR 3,

OFFSHORE DRILLING PLATFORM Original Filed Feb. 9, 1959 5 Sheets-Sheet 4INVENTOR. EDWlN I. SWATEK,JR.

ATTORNEYS.

July 20, 1965 :.-P. SWATEK, JR

OFFSHORE DRILLING PLATFORM Original Filed Feb. 9, 1 959 INVENTOR. EDWINP. SWATEK,JR.

ATTORNEYS.

United States Patent This application is a continuation of my copendingapplication, Serial No. 792,112, filed February 9, 1959.

This invention relates to an earth drilling or similar apparatus for usein drilling operations over a body of water, and which is generallytermed an oifshore drilling rig, and the present invention is for theplatform on which the drilling rig is mounted, and from which thedrilling operations are conducted. While the platform is designedprimarily for drilling purposes, it may also be used in variousconstruction projects where a stable over- Water platform is needed.

The primary object of my invention is to provide a floating hull withlegs that may be raised to enable the hull to be towed over water to orfrom its place of use with out requiring excessive draft, and which maybe lowered and driven, even in relatively deep water into the strataunder the water, together with provision for elevating the platformabove the level of wave action, and to lower it when the platform is tobe moved or located elsewhere.

In general the platform comprises a water-tight steel hull which isbuoyant so that it may be towed from place to place, and which providesadequate deck space for the drilling rig and other equipment, livingquarters for the drilling crew, and other space necessary for theoperation to be carried on. There are a number of guides, at least oneat each corner, through which the legs may be raised and lowered.Hydraulic jacks are associated with the guides for effecting verticalmovement of the platform up and down the legs.

My invention may be more fully understood by reference to theaccompanying drawings, in which:

FIG. 1 is a side View of a platform embodying my invention, showing itin position with the platform elevated above the level of the waves;

FIG. 2 is an end view of FIG. 1;

FIG. 3 is a plan view of the platform;

FIG. 4 is an elevation of one of the legs, all of which are alike;

FIGS. 5 and 6 are transverse sections through one of the legs in theplane of lines VV and VI-VI respectively of FIG. 4;

FIG. 7 is a top plan view of one of the legs;

FIGS. 8 and 9 are elevations at right angles to each other of the upperend of one of the legs;

FIG. 10 is a side elevation, partly in section, of the driver locatedwithin one of the legs;

FIG. 11 is a fragmentary view showing in side elevation on a largerscale than FIG. 2 the guide'at one corner of the platform with thehydraulic jacks retracted;

FIG. 12 is a similar view with the jacks extended;

FIG. 13 is a transverse section of a single leg guide at one corner ofthe platform, the section being on line XIIIXIII of FIG. 11;

FIG. 14 is a front view of FIG. 12; and

FIG. 15 is a schematic diagram of the fluid pressure system for thejacks.

Referring to the drawings, 2 designates a platform provided with awater-tight buoyant metal hull which may be made as a single unit or ofsections secured together. As here shown, it is substantially square,but it need not be square or even rectangular, and over which is a deck3,195,313 Patented July 20, 1965 2a. At each corner of the platformthere is a vertical leg guide 3, formed of structural steel members,including vertical parallel I-beams 4 secured to the platform and hulland connected by structural cross members 5, so as to provide a framethrough which the leg 6 extends vertically.

Each leg 6 comprises a long length or joined length of steel pipe, andextending along diametrically opposite sides of the pipe from the lowerend to a level near but below the top of the leg are steel channels 7faced against the exterior of the pipe and welded thereto. Thesechannels form rib-like projections down the pipe, and transverseopenings or keyways 8 are formed therethrough at intervals. The lowerend of each leg terminates in a cutting edge 9 (see FIG. 4) and has aninternal reinforced concrete plug 921 near the bottom, while there areone or more vent openings through the leg below the plug.

There is an internal weight 10 (see FIG. 10) inside each tubular legwhich is movable vertically within the leg. It is here shown as a metalshell with a lifting bail 11 at the top, and having guide fins 12 aroundits periphery to keep it centered in the leg, and is filled withreinforced concrete 13. A sheave 14, which for clarity of illustrationis shown only in FIGS. 7, Sand 9, is mounted on the top of each leg overwhich a cable 15 attached to the bail 11 may pass to the drilling rig orother hoisting mechanism to raise the weight and drop it, so that eachleg may be driven into the strata at the bottom down to bed rock. Thedrilling rig or hoist for this purpose is of any usual construction andforms no part of the present invention.

The leg guide 3 adjacent the bottom thereof is provided with blocks orchocks 16 that fit about thetubular leg and form channels to receive theribs 7 on the leg 6. As viewed in FIGS. 11 and 12, steel bars or keys(not shown) can be thrust horizontally through openings 17 in thesechocks and through the openings 8 in the ribs '7 to hold the platformand'legs against relative vertical movement.

In addition to the cross member 5 the leg guide has cross members 5a atthe top (see'FIG. 14) to which are secured, or against which bear, thetops of rams 18 operated by fluid pressure cylinders 19, the cylinderand ram constituting a jack. The base of the jack is attached to astructural frame 20 movable vertically in the leg guide. Removable steelbars or keys 21 are passed through the openings 8 of channels 7 underthis frame 29' to hold it against relative movement on the leg. Thesebars or keys are similar to the ones that are passed through openings 17in the chocks, as above described.

Flexible fluid pressure lines 24 lead to the upper end of each cylinder19, and a similar connection 25 leads to the bottom of the cylinder.Referring to FIG. 15, there is a fluid pressure reservoir 26 on theplatform, and 27 is a pump that supplies hydraulic fluid under pressurethrough pipe 28 to manifold 29 leading to four-way valves 30, therebeing one valve for the jacks at each corner of the platform. Pipes 31and 32 connect to lines 24 and 25, respectively. A return manifold 33connects each four-way valve with a return pipe 34 leading to thereservoir. Dotted line 35 indicates a pipe leading to an auxiliaryreservoir 36 and hand pump 37 to be used if the primary pump 27 fails.

The derrick or hoist or other structures carried on the platform form nopart of the present invention, but there may be a derrick 38, while 39indicates schematically the motor and hoist drum for the device. Casingpipe storage is diagrammatically indicated at 46 and 41. There is anopening or well 42 through the hull at the base of the derrick throughwhich drilling operations are is towed to the place where drilling is'tobe done, and the keys or bars 21 are then Withdrawn to lower the legs tothe bed of the body of water. The legs are then driven one at a time,this being done by operating the internal weight of each leg, raisingthe weight and dropping it to drive the leg down to a solid footing.When the-legs are set, the bars 21 are inserted under the frame 243, to

pass through the openings 8 in the side ribs on the legs,

At this time. there are no similar bars in the openings 17 a in thechecks. The pressure of the jacks, thrusting up on the members 5a, liftthe platform, the thrust on the base of the jacks being transmittedthrough the frame 20, and bars 21 to the legs. When the jacks are fullyextended, bars 21 are thrust through openings 17 of chocks 16 andregistering openings 8 in the ribs 7 on the legs, so that the platformcannot now move down and the bars 21 under the. frame 20 are removed andthe jacks retracted. After the jacks are retracted the bars 21 are againplaced under the frames 20, bars 21 are removed from the chocks 16 onthe platform, and the operation is-repeated. This procedure is continueduntil the platform has climbed up the legs sufficiently above the waterlevel to be clear of wave action. Then, with the aid of a diver, bracingcables 44 are secured to the legs and platform to steady the structureagainst side sway.

When the platform is to be moved, it is lowered in steps similar to themanner in which it was raised, except the retracting of the jacks isused to lower the platform, whereas the extending action of the jacks isused in raising it. The legs can then usually. be pulled by jackingagainst the hulls buoyancy, that is the jacks are operated to push theplatform down into the water to submerge its normal Water line, whereasthe platform is pushed up by its buoyancy, thus exerting a thrustupwardly on the legs, and wave action at thistime may assistrtheoperation. If

this does not succeed, water can be jetted into the earth around thelegs in a manner well known in the art, or if this is not successful,they can be cut off at the. earth level. After the legs are free of thebottom, they can be raised by operation of thejacks to the extentdesired and the platform moved to a new location.

My invention therefore provides an offshore drilling platform that maybe constructed completely on shore;

towed to the place of use, and then anchored and elevated clear of thewater with no equipment other than that on the platform itself, When itisto be moved to another site, it may also be operated to pull its ownsupporting legs out of the bottom and lift them to draft depth.

A boat platform 45 may be attached to vertical struts 46 attached to theplatform and to oneof the legs. A ladder 47 may then be placed on thisboat platform and lashed to the drilling platform. Removable bumperstrips are indicated on the legs at 47, these being at water level.

While I have shown and, described a preferred construction embodyingmyinvention, various changes and modifications may be made thereinwithin the contemplation of my invention and within the scope of thefollowing claims, and it will be apparent that any number of legsrnay beused, depending on the size and weight of the 4 ing a buoyant hull, adeck fixed to the hull for supporting a drilling rig, a plurality of legguides fastened to the hull, the guides each including an openworkstructure with an upper rectangular framework rigidly attached to thedeck by depending column members anda lower rectangular length of theribs, a chock attached to the guide with flanges in relative slidingengagement with'the ribs and having aligned spaced openingsextendinghorizontally, the chock openings. being in alignment withthe slottedopenings ofthe ribs, pins passed through the slotted openings of theribs and of a length greater than the width of the lower framework ofthe. guide whereby the lower framework is supported on'the pins forelevation of the upper frameworkand deck upon extension of the jack, thepins being insertedinto the openingsof the checks and aligned slottedopenings of the ribs for fixing the location of the guide on .the ribsof the leg when pins are removed from supporting position beneath thelower framework such that retraction of the jack elevates the movablelower framework toward the upper framework,

the pins being reinserted beneath the lower framework and removed fromthe chock openings for subsequent extension of the jack. and lifting ofthe deck and upper framework for incrementally raising the hull and deckon the legs.

2. In an offshore drilling rig, the combination comprising abuoyant-hull, a deck fastened to the hull, a plurality of leg guidesspacially arranged on the hull, each leg guide including an upperportion rigidly connected with the deck and in verticallyspaced-relation thereto, a leg slideably engaged through each guide andthrough the deck, a lower guide portion spaced intermediate the upperguide portion and the deck and vertically movable with respect to theleg, each leg having diametrically opposed ribs extendinglengthwise onthe leg and provided with a plurality of transversely slotted openingsspaced vertically of the ribs, a jack connected to the upper and to thelower guide portions and extensible and retractable therewith, chocksrigidly connected tothe deck and having flanges with transverselyaligned openings between which a leg rib, is guidingly supported formovement in vertical direction, pin engageable through the slottedopenings of the ribs of each leg and extending beneath the lower movableportion of the guide whereby the extension of the jack raises the guideupper portion and the deck simul taneously while the guide lower portionis supported in fixed relation to the leg on the pins, the pins beingslideably engaged through aligned openings of the Chocks and ribs forlocking the guide in position on the leg, the pins engagingthe chocksbeing removed when the pins are inserted in the slotted openings of theribs beneath the movable lower portion of the frame afterretraction ofthe jack for subsequent incremental elevation of the deck and guiderelative to the leg by extension of the 'jack.

References Cited by the Examiner UNITED'STATES PATENTS 216,042 6/79 LeGrand -19 2,540,679 2/51 Lelfaille. 2,775,869 1/57 Pointer 6l" 46.52,837,897 6/58 Nedderman .61-46.5 2,944,403 7/60 Smith 61-465 EARL I.WlTMER,.P1-imary Exairziner. JACOB SHAPIRO, Examiner. I

1. IN AN OFFSHORE DRILLING RIG, THE COMBINATION COMPRISING A BUOYANTHULL, A DECK FIXED TO THE HULL FOR SUPPORTING A DRILLING RIG, APLURALITY OF LEG GUIDES FASTENED TO THE HULL, THE GUIDES EACH INCLUDINGAN OPENWORK STRUCTURE WITH AN UPPER RECTANGULAR FRAMEWORK RIGIDLYATTACHED TO THE DESK BY DEPENDING COLUMN MEMBERS AND A LOWER RECTANGULARFRAMEWORK IN VERTICALLY SLIDING CONNECTION WITH THE VERTICAL COLUMNS, AJACK POSITIONED BETWEEN AND CONNECTED TO THE UPPER AND LOWER FRAMEWORKSFOR MOVING THE LOWER FRAMEWORK TOWARD AND AWAY FROM THE UPPER FRAMEWORK,LEGS GUIDINGLY SUPPORTED THROUGH THE OPENWORK STRUCTURE AND SURROUNDEDBY THE UPPER AND LOWER FRAMEWORKS OF THE GUIDE FRAME, RIBS ATTACHEDALONG THE LENGTH OF EACH LEG AND PARALLEL WITH THE LEG AXIS, EACH RIBHAVING SLOTTED OPENING EXTENDING HORIZONTALLY AND SPACED VERTICALLYALONG THE LENGTH OF THE RIBS, A CHOCK ATTACHED TO THE GUIDE WITH FLANGESIN RELATIVE SLIDING ENGAGEMENT WITH THE RIBS AND HAVING ALIGNED SPACEDOPENINGS EXTENDING HORIZONTALLY, THE CHOCK OPENINGS BEING IN ALIGNMENTWITH THE SLOTTED OPENINGS OF THE RIBS, PINS PASSED THROUGH THE SLOTTEDOPENINGS OF THE RIBS AND OF A LENGTH GREATER THAN THE WIDTH OF THE LOWERFRAMEWORK OF THE GUIDE WHEREBY THE LOWER FRAMEWORK IS SUPPORTED ON THEPINS FOR ELEVATION OF THE UPPER FRAMEWORK AND DECK UPON EXTENSION OF THEJACK, THE PINS BEING INSERTED INTO THE OPENINGS OF THE CHOCKS ANDALIGNED SLOTTED OPENINGS OF THE RIBS FOR FIXING THE LOCATION OF THEGUIDE ON THE RIBS OF THE LEG WHEN PINS ARE REMOVED FROM SUPPORTINGPOSITION BENEATH THE LOWER